This invention relates to a low insertion-withdrawal force electric connector used for connecting wire harnesses together or for connecting a wire harness to an electric device. It also relates to a low insertion-withdrawal force electric connector used, for example, for connecting many electric wires.
A conventional electric connector, in which by fitting female and male connectors relative to each other, a pair of terminals contained therein are electrically connected together, has a locking device for maintaining a connected condition which includes a lock arm and an engaging projection. A sensory indication of a locked condition at the time of engagement of the lock arm with the engaging projection, as well as visual confirmation of the fitting is obtained.
However, the touch indication for the operation varies depending on the speed of fitting of the connectors, the atmosphere of the use, differences between individuals, and so on. The visual inspection may also involve an erroneous judgment or an overlook, and thus both may fail to provide positive confirmation means.
Therefore, as shown in FIGS. 1A and 1B, Japanese Laid-Open (Kokai) Patent Application No. 241778/89 discloses a construction in which a lock plate b movable between a locked position and an unlocked position, as well as a holder portion c for holding the lock plate b in the locked position, is provided on a female connector a, and a male connector d is provided with a lock portion e for locking the lock plate b upon completion of the locking thereof relative to the female connector a. At the time of the locking, a short-circuit piece f mounted on the lock plate b is abutted against a short-circuit terminal g to turn on an alarm lamp, thereby enabling the fitting to be electrically confirmed.
In the electric connector as shown in FIGS. 1A and 1B, the operation for fitting the female and male connectors a and d is independent of the operation for locking the lock plate b, and therefore there is a risk that the operator may finish the operation, forgetting to lock the lock plate b. And besides, because of a multi-pole (increased number of connector terminals) design of the connector, a large fitting force is required for the fitting between female and male terminals, and therefore there are occasions when the operation can not be carried out easily.
On the other hand, when the number of poles (i.e., the number of connector terminals) is increased, a greater force is required for fitting and disengaging female and male connectors relative to each other because of increased frictional resistances between terminals, and therefore the operation can not be carried out easily.
In view of the above, in order to reduce the insertion and withdrawal force, Japanese Laid-Open (Kokai) Patent Application No. 157076/89 discloses a construction in which a slide cam is mounted on a hood of a concave housing in perpendicularly intersecting relation to axes of terminals, and a cam track with which a cam follower for the slide cam is engaged is provided on a convex housing.
In the electric connector of this type, as shown in FIG. 2, as compared with the force (indicated by a curve fo) required only for the fitting of female and male terminals, the fitting can be done with a smaller force (indicated by a curve f1) thanks to the provision of the slide cam; however, when the convex housing is fitted a certain depth d, the insertion force becomes substantially constant (k1), and therefore the operator does not perceive any sensory indication of the completion of the fitting operation, and hence may stop the operation before completion which leads to a risk that an incomplete fitting may be encountered.